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rssN 1822-508X

KALINAS LINIVERSITY OF TECHNOLOGYVYTAUTAS MAGNUS UNIVERSITYLITHUANIAN E,NERGY NSTITUTE

RIGA TE,C HNIC AL LII.{IVE,RSITYHYDROGEN ENERGY ASSOCIATION

4'd International Conference

RADIATION INTERACTION WITH MATERIALAND ITS USE IN TECHNOLOGIES 2012

Kaunas, LithuaniaMay 14-17,2012

Program and materials

AT\r-' TECHNoL0GTJA

KAUNAS . 201 2

I

ysics,2006, Volurne 88, Issue 16,

al. Slruclural and spectroscopicleposited at low temperature on11 69 -4332: NORTH-HOLLAND,

f amorphous silicon-carbon filmstechnique// Joumal of Physics:E, 1999, Volurne 11, Number 26,

infra-red optical rnaterials fromisronal plasma process// Appliedtte of Physics, 2010, Volume 96,

al. Structures, C-H and C-CH3Jrocarbons llPhys. Chem. Chem.Le 22, p. 5084-5088;

Variation of Oxygen-to-Carbon8; Arlington, TX), conference.816;

retallic compounds, Volume 37,46-9, ISSN 0584-8555.

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PREPARATION AND CHARACTERIZATIONOF SILVER/ POLYVINYLPYRROLTDONE

COMPOSITES FOR OPTICAL APPLICATIONS

Judita PuiSol, Asta Guobiendl'', Algirdas Lazausk?sl'2,Igoris Prosydevas2, Sigita Ponelyt6l'3,

Ramiinas Nauj okaitisl, Alvydas JotautisllDepartment of Physics, Kaunas [JniversiQ of Technology,

2 In.stitute of Materials Science, Kqunas Universilt of Technologt,3 Internationol Study Center, Kaunas University of Technology,

A ddres,s : Stu den t4,s tr. 5 0, LT- 5 I 3 6 8 Kauna s, Lit ltu an i a,'

E -ma il : i u dit a.pu is o @,. ktu. lt

Abstract

Silver nanoparticles dispcrscd in polyvinylpyrrolidone (PVP) nanocompositcswere prepared by photoreduction of silver nitrate (AgNO3) in ethanol solution of PVP.The prepared nanocomposite films were subjected to ultraviolet (UV) irradiation at

room temperature for different times. The effect of UV-irradiation has been studied byUV-Visible spectrophotometry. The appearance of surface plasmon resonance (SPR)band at - 415 nm in the UV-Visible absorption spcctra of silvcr nanoparlicles colloidssolution and in the thin films indicates the presence of the silver nanoparticles. UV and

thermal treatment effbct on SPR of Ag/PVP thin films were also determined.

Keywords: si/ver nanoparticles, UV-VIS, PVP, ethanol.

Nanocomposite materials consisting of metallic nanopafticles incorporatedin or with polymers have attracted much attention due to their distinct optical,electrical and catalytic properlies. They have potential applications in the fieldsofcatalysis, bioengineering, photonics, biosensors, actuators, electrodes for fuelcells, optical and optoelectronic devices [1-7]. The most popular method lorpreparation of metal nanoparticle colloid is chemical reduction of silver salt inthe presence of any stabilizing agent. Most commonly used stabilizing agentsare polymers and surfactants. A successful preparation of nanopadicles isdetermined by the ability to produce particles and long stability, given theirtendency to rapidly agglomerate in aqueous solution 11-2,51.

A number of organic materials are known as protective agents forpreventing silver parlicle coalescence, but PVP exhibits the best stabilizingproperlies. PVP is water soluble, biocompatible and nontoxic polymer. As a

host matrix it is important because of it has a good reducing and capping agentfor metal and semiconductor nanoparticles [4-6]. Further, it is well quoted inthe literature that size, shape and dispersity of the embedded parlicles can betuned through gamma, ultraviolet and charged pafiicle irradiation [4-6]. The

383

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water soluble nanocornposites are very irnportant in bioscience and medicine

applications. change distilled water to ethanol usually used in Ag/pVp colloidsynthesis influenced viscosity of sirnple PVP solutions. on thc other hand

according literature [3-5] ethanol has no effect on the polymer conformation,The changes observed in the viscosity reflect the viscosity of thc background

solvent.In the present work, synthesizing PVP-r.ranocomposites through in-situ

chemical reduction method in ethanol are presented. A systematic study of the

eff-ect of ultraviolet irradiation on the optical and structural properties of this

nanocomposite has been carried out.Silver nitrate (AgNO3 analytical reagenr) and polyvinyl pyrrolidone (pVp)

average MW - 58 000) and sodiurn dodecyl sullare (SDS) (M\\,-288.38)wereobtained lrom Sigma Aldrich. Ethanol (96.3 %) obtained frorn JSC "Sturnbras".For this purpose, PVP (2g) was dissolved in ethanol (8 ml) fbllowed by

addition of 50 pl AgNo3 (l mM) and 200 pl of SDS. Solution was inadiatedby UV (LAMPI5WES -UV 366 nm, 15 W) for I hour ant room rernperatureand in dark container. The change of the colour of the solution from transparentto yellow during UV irradiation indicates lonlation of silver nanoparliclcs inethanol. Thin fllms of Ag/PVP werc deposited on pretreated glass substratcs bvspincoating. The spin coating specd was 1000 rpm ant time 60 s. Ag/pvp filnswere dried in convection oven at 70 oC for 120 minutes to remove solvents.Aflerwards, the prepared films were subjccted to ultraviolet irradiation at rogurtemperatllre for diflerent tin-ies with maximurn up to 10 minutes. UV lamp(APlrI-250, 12500 hn) was used witli 350 - 450 nm wavelengths. Halogenconvection (Magitec MT-1112, 1400w, 125 oc, t-i0 min) oven was used lorAg/PVP thin fihns thern"ral treatrnent. UV-VIS absorbance lneasurements wereperlonncd with Jasco v-650 double-bearn spectrophotorleter with aphotorlr-rltipl ier tube detector.

Ag/PVP thin films were transparent and light yerlow without surfaceplasrnon resonance (SPR) peak in UV-vIS absorbance spectra. UV inadiationinduced results in spontaneous aggrcgation of Ag nanoparticles, accornpaniedby strong enhancernent at 415.6i nm ancl a shift torvard longer wavelengths olthe absorption peak due to surface plasrno' resonance (spR). Longer UVirradiation leads initially to liagrlentation of the aggregates and then to partialcoalescence of the nanoparticles rvith a corresponclir.rg shilt of SPR towardslonger wavelengths and increasing intensity ol thc SpR peak. SpR peak wasobscrved in the range of ,1 l5 - 420 nrn suggest that Ag particles have sphericalshape. Ag nanoparticles size according Mie carculations for spherical Agnanoparticles PVP is 2zl nm. The starting point ol the synthesis is theproductiorr ol a silver nitrare (Aglr,lo.) solution. when silvcr nitrate is

dissolved it splits into a positive silver ion ( lg,, ) ancl a negative nitrate ion

(,VO' ).

381

)ortant in bioscience and medicinerolusually used in Ag/PVP colloid'VP solutions. On the other handfect on the polymer confonnation.rct the viscosity of the background

'P-nanocomposites through in-situresented. A systematic study of theal and structural properties of this

t) and polyvinylpyrrolidone (PVP)I sulfate (SDS) (Mw:288.38) were%) obtained from JSC "Sturnbras".d in ethanol (8 ml) followed bypl of SDS. Solution was irradiated

) for I hour ant room temperatureour ofthe solution from transparentormation of silver nanopafticles ined on pretreated glass substrates by0 rpm ant time 60 s. Ag/PVP filmsr 120 minutes to remove solvents.:d to ultraviolet irradiation at roomnum up to 10 rninutes. UV lamp- 450 nm wavelengths. Halogeni oC, t=10 min) oven was used fortIS absorbance [leasurements wereeam spectrophotorneter with a

and light yellow without surfaceabsorbance spectra. UV irradiationof Ag nanoparticles, accompaniedshift toward longer wavelengths of)n resonance (SPR). Longer UVfthe aggregates and then to partial,nesponding shift of SPR towardsi of the SPR peak. SPR peak wasest that Ag particles have spherical4ie calculations for spherical Agrg point of the synthesis is thesolution. When silver nitrate is

(Ag,,,) and a negative nitrate ion

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416.16 nm

Wavelength, nm

Fig. 1 UV-VIS spectra of Ag nanoparticles in PVP after UV

inadiation a) 2 min, b) l0 min c) 3 min

Formation of Ag nanoparticle ( Ag' ) is a result of silver ions ( ,4g., )

reduction by receiving an electron from a donator:

Ag),,+e' = Agn (1)

In solution in ethanol silver reduction reaction could be describe by eqtlation

[6]:

2Agi,, + CTH,OH + H rO -+ 2Ago + C,H ,O; + 3H- Q)

when the silver seeds, has been formed it starts to grow and continue the

gro*in until the equilitrium between the final nunopu.ti.1"s and the (Ag*) of

ihe solution is reaihed. In presence in solution PVP silver ions reduction and

stabilization could be describe synthesis could be described as:

Ag. + PVP -+ Ag(PVP). (3)

we have good agreement of study [6-7] of the interaction between PVP and the

growing rilu.. nunoparlicles results, which presents that in the case of particles

41.5

416.02 nm

6l nm\

d

-oa-o

0.1

385

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with cliameters belor.v 50 lur the nitrogcn atotr-r of interacts rvith silver and

fbrr.r-rs a protective shell. Furthcr silvcr nanoparticles grolvillg. dcfragnlcntrtion

and coalesces was induced also by UV irradiation. Thern"ral treatment ol

Ag/PVP thin fllms below the boiling point ol PVP induced silver nanoparticles

aggregation in PVI, with a corresponding redshif't and decrcasing intensity ol

thc SPR peak.

Acknolvledgemcnts

This rescarch was ttinded by a grant No MIP-058/2011 fiom thc Sciencc

Council of Lithuania. Special thanks go to Nijole Studinskicnq for

recomrnendations and productive discr,rssior.rs. Research Council ol Lithuania

and Center for Hydrogen Energy Technologies ol Lithuanian Energy lnstinltc

arc gratefirlly acknowledged.

Rel'erences

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plasmon resonance biosensors. Nanon-redicine, 1, 2006, 219-228 p.

2. l'hakkar K. N., Mhatre S. S., Parikh R. Y. Biological synlhcsis of mctallic

nanoparticlcs. Nanomedicine,6 . 2010, 257 262 p.

3. Grililths PC, Ilirst N, Paul A, King SM, Ileenarr RK, Farley R, E,lfcct of cthanol

orr the interaction bcnvcen poLy(vinylpyrrolidonc) and sodiurn dodccyl sullatc,-

Larrgrnuir, 16, 2004 I 6690.1- l-3 p.

1. Wang S.-R., 'fseng, W. J., Aggrcgate structlrre and crystallitc sizc of platinunr

nanoparticlcs synthcsizcd by ethanol redr-rction.- Journal ol Nanoparticle, I 1, 2009.

9;17_953 p.

5. Ayyappan S., Srinivasa Gopalan R., Subbanna G. N. ancl Rao C. N. R.Nanoparticles o1- Ag, Au. Pd, and Cu produced by alcohol rcduction of thc salts.-

Journal of Mate rials Rcscarch. 12 1991 ,398-401p.

6. ChoLr, K.-S., Lu, Y.-C., and Lcc, H.-H. Effect of alkaline ion on tl.re mechanisnt

anrl kinetics of cl'rcnrical rcduction ol silver.- Materials Chernistry and I']hysics 94.

2005, ;129 :133 p.

1. Wans H.. Qiao X., Chcn.l., Wang X.. Ding S. Mechanisrns of PVP in the

preparation of silvcr nanoparticles. - Materials Cihcmistry and Ph1,sics, 9:1. 2005.zfl9_,153 p.

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